import java.util.ArrayList;


public class Maratona 
{
	
	private int n;
	
	private int m;
	
	private ArrayList<Integer> p = new ArrayList<Integer>();
	
	public Maratona ( int n , int m , ArrayList<Integer> p )
	{
		this.n = n;
		this.m = m;
		this.p = p;
	}
	
	public char execute()
	{
			int velho = p.get(0);
			char res = 'S';
			
			for ( int i = 1 ; i < n ; i++ )
			{	
				int novo = p.get(i);
		
				if ( novo - velho > m )
					res = 'N';
				
				velho = novo;
			}
			
			System.out.println(res);
			return res;
	}
	
}
